before:
  this_module = 'posix.sys.statvfs'
  global_table = '_G'

  M = require(this_module)


specify posix.sys.statvfs:
- context when required:
  - it does not touch the global table:
      expect(show_apis {added_to=global_table, by=this_module}).
         to_equal {}


- describe statvfs:
  - before:
      statvfs = M.statvfs

  - context with bad arguments:
      if statvfs then
         badargs.diagnose(statvfs, "(string)")
      end

  - it returns a PosixStatvfs:
      if statvfs then
         expect(prototype(statvfs("/"))).to_be "PosixStatvfs"
      end
  - it fetches statistics for a mounted file system:
      if statvfs then
         sv = statvfs "/"
         expect(type(sv)).to_be "table"
         for _, field in pairs {"f_bsize", "f_frsize", "f_blocks", "f_bfree",
              "f_bavail", "f_files", "f_ffree", "f_favail", "f_flag", "f_namemax"}
         do
            expect(type(sv[field])).to_be "number"
            expect(sv[field] >= 0).to_be(true)
         end
      end
  - it returns a non-negative value from fsid: |
      -- Merge this back into the previous example when #102 is fixed
      if statvfs then
         sv = statvfs "/"
         pending "issue #102"
         expect(sv[field] >= 0).to_be(true)
      end